Cellulose-ether film and composition for making the same



Patented Sept. 8, 1925.

UNITED STATES JOHN M. DONOHUE. OF ROCHESTER, NEW YORK, ASSIGNOR '10EASTMAN KODAK PATENT OFFICE.

COMPANY, OF ROCHESTER, NEW YORK, A CORPORATION 01' NEW YORK.

CEIiLULOSE-ETHEB FILM COMPOSITION FOR MAKING THE SAME.

Ho Drawing.

To all whom it mag concern:

Be it known that 1, JOHN M. DONOHUE, a citizen of the United States ofAmerica, residing at Rochester, in the county of 5 Monroe and State ofNew York, have invented certain new and useful Improvements inCellulose-Ether Films and Compositions for Making the Same, of which thefollowing is a full, clear, and exact specifica- 0 tion. v v

This invention relates to cellulose ether films and compositions formaking the same. One object of the invention is to provide films inwhich the flexibility is maintained even under severe conditions, suchas prolonged heating. Another object of the invention is to provide aflowable film-formin composition which will be stable and will producefilms which will'likewise be stable and maintain their flexibility;Other objects will hereinafter appear.

In U. S. Patent No. 1,188,376, Lilienfeld, June 20, 1916, there aredisclosed a.

' series of alkyl ethers of cellulose. Certain of these are practicallyinsoluble in water,

and the present invention relates primarily to ethers having thatproperty, although it is not restricted to them. When such ethers aremade into films for difierent purposes,

such as photographic supports or protective coatings, it is desirable,under circumstances whlch are often met with in ractice, that theywithstand prolonged eating without becoming brittle. In testing 36 such}filmsto determine whether they will withstand the conditions ofpractice, se-

Vere tests are customarily made by heating them for several weeks at atemperature 0f"65 C. It is desirable that the films re- 40 main flexibleeven after twelve weeks of continuous heating at the above tempera?ture. v

' I have discovered that films which maintain their flexibility underthe above dey 46 scribed test may be prepared by incorporating one ormore of the acetic acid esters of the polyhydroxy benzenes, such as themonoacetate or diacetate of pyrogallol, resorcinol,

catechol, hydroxyquinol and hydroquinone. 50 Moreover the requiredproportion of such stabilizers in the film is comparatively small. Thestabilizing substance or mixture of such substances is incorporated withthe cellulose ether by the aid of a commonsolvent,

I Application filed February 28, 1923. Serial No. 820,614.

the resulting solution or dope bein flowed or deposited and the filmsformed y evaporation of the volatile ingredients in the way understoodby those skilled in the art. The stabilizers beingof high boiling pointand consequent low volatility remain in the final film in suflicientproportion.

For example, I may dissolve 20 parts by weight of cellulose ether, saywater-insoluble ethyl cellulose and 2 parts of hydroquinone diacetate in140 parts of a volatile solvent mixture of methyl acetate and me-. thylalcohol. The ratio of methyl acetate to methyl alcohol may, of course,vary, 126

parts of the former to 14 of the latter being useful. The percentage ofcellulose ether can, of course, be varied also, .as well as the quantityof stabilizer. Where thin films or coatings are to be made by applyingthe composition asa lacquer or varnish,

the amount of volatile solvent will be increased until the dope reachesthe required thinness, as will be understood by those skllled in thisart. With the proportion given in the exam lo a dope is produced whichmay be use inthe preparation of films for photographic purposes in theapparatus and by the methods customarily employed.

' Films produced from the hereinabove described compositions containsufiicient Sta-- bihzer, such as hydroquinone diacetate in combinationwith the colloidized cellulose ether to maintain their flexibility, evenwhen theyare heated for twelve Weeks at 65 (3.

In practical use, wherethey are unlikely to meet any severer conditions,they maintain the necessary flexibility in a reliable way.

Stabilizers do not have to be emplo ed alone, but other substances maybe adds to the dope whichrimpart additional properties to it, such forinstance, as triphen l or tricresyl phosphate, 'monochlornaplithalene,camphor, etc. The ingredients are of the ordinary commercial typesufliciently purified for the process of film manufacture so as to givedopesyieldin films having the proper relative freedom rom color.

Having thus describedmy invention, what I claim as new-and desire tosecure by Letters Patent is: 1

1. A composition of matter comprising cellulose ether and an acetic acidester of a polyhydroxy benzene,vthe ingredients being t homogeneouslymixed in unprecipitated form.

2. A composition of matter comprising cellulose ether and hydroquinonediacetate, the ingredients being homogeneously mixed in unprecipitatedform.

3. A composition of matter comprising cellulose ether and an acetic acidester of a polyhydrox benzene dissolved in a volatile common so vent.

4. As an article of manufacture, a film longing the flexibility of thefilm under prolonged heating at 65 C;

5. As an article of manufacture, a film comprising cellulose ether and astabilizer of hydroquinone diacetate.

6. As an article of manufacture, a transparent flexible film for use asa photographic support comprising water-insoluble ethyl cellulose andhydroquinone diacetate.

Signed at Rochester, New York this 14th day of February 1923.

' JOHN M. DONOHUE.v

